Extreme metal, more than almost any other genre, is a game of oneupmanship. Each blitzkrieg solo and blast beat faster than the others, each growl more terrifying than the last. It's a field that demands you stick out or get lost in the competition so when beastly guttural growls and soaring operatic vocals become the norm, where else is there to go?

Rainer Landfermann has carved out a place for himself as one of the most inimitable voices at the fringes of metal. During his time with genre titans Bethlehem, his performance was described as "one of the sickest and most extreme voices you'll ever hear from a human being". Two songs from his tenure with the band landed on the soundtrack for the twisted indie cult classic Gummo. Since then, Landfermann has gone solo, releasing his latest album Mein Wort in Deiner Dunkelheit. It's a real horrorshow collection of black metal, industrial and melancholic symphony tied together with some dizzying bass playing and blood-curdling screams that sound as if they were lifted right out of the most vicious slasher flick.

Sombre bowed double bass courtesy of Rainer's brother Robert carves out the woozy intro to 'Langsam, hinters Licht' to open the album. Landfermann's bass guitar takes melodic duties, duetting with the brief refrain of restrained whispers. It doesn't take long for the demon to come out and his unmistakable shriek instills an impending sense of dread. In between verses, he shows off his virtuosic bass playing, working with the dexterity of a premier jazz musician working within in a Wagner-like classical realm. 'Kuntsvoll' serves as the album's jumping-off point with Landfermann leading it off with an arresting screech. Imagine if Robert Plant's opening howl from 'Immigrant Song' were coming from the depths of the solitary confinement wing of a decrepit asylum. The vocals are so uninhibited by convention that it is frighteningly jarring, even to seasoned black metal fans. But like anything that is extruded from the norm, it sinks its teeth in your brain creating an indelible hook.

Later album tracks like 'Hingabe' give some brief respite from the dour onslaught with swinging jazzy sections bridging the maniacal blast beat rantings. 'Genius Drang' leans into the deep cavern chorals and 'Urspr√ľngliches' fully inhabits the jazz club with Robert's double bass laying down the groundwork for pianist Pablo Held to tickle the ivories. Rainer still manages to overlay his squeals of terror on this subdued downtempo number. It's hard to tell how it works but it somehow does. Is it all that different from Mariah Carey or Toni Braxton belting out in pain over a jazz ballad?

Rainer Landfermann is pushing the bounds of a genre that consistently feels as if its at its limit. His wild cries are creative expression at its most unbridled. On top of that, there is no denying his incredible prowess at his instrument. Mein Wort in Deiner Dunkelheit is the definition of a challenging listen but with an open mind, you can see the beauty in the chaos.